Abstract

Wavelength-matched vibrational excitations of ethylene molecules using a tunable carbon dioxide laser were employed to significantly enhance the chemical vapor deposition(CVD) of diamond in open air using a precursor gas mixture of , acetylene , and oxygen . The -wag vibration mode of the molecules was selected to achieve the resonantexcitation in the CVD process. Both laser wavelengths of 10.591 and were applied to the CVD processes to compare the excitations and diamonddepositions. Compared with produced by common lasers, the laser wavelength of is much more effective to excite the molecules through the -wag mode. Under the laser irradiation with a power of 800 W and a wavelength of , the grain size in the depositeddiamondfilms was increased by 400% and the film thickness was increased by 300%. The quality of the diamond crystals was also significantly enhanced.

Received 18 November 2008Accepted 10 January 2009Published online 17 March 2009

Acknowledgments:

The authors would like to thank Dr. D. Doerr and Dr. D. Alexander in the Department of Electrical Engineering at the University of Nebraska-Lincoln (UNL) for providing convenient access to their SEM system. This work was financially supported by the U.S. Office of Naval Research (ONR) through the Multidisciplinary University Research Initiative (MURI) program.